Spark-plug.



A. ST. JAMES. SPARK PLUG.

APPLICATION F ILED 00L 9. ms.

Patented Mar. 5, 1918.

I I l r Y glwuemtoz 13. id!- (Email UNITED STATES PATENT OFFICE.

ALFRED ST. JAMES, 013 BROOKLYN, NEW YORK.

SPARK-PLUG.

Application filed October 9, 1916.

To all whom it may concern:

Be it known that l, ALIrREI) ST. JAMns, a

citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful. Improvements in SparlcPlugs; and I do hereby declare the following to be a full, clear, and exact description of the inrention, such as will enable others skilled in the art to which it appcrtains to make and use the same.

This invention relates to spark plugs.

The object of the invention is to provide a spark plug of such character that. it will be more positive and certain in operation than those plugs which are known to me, an d that. it is provided with an improved form of electrodes whose cotiperation is less likely to be affected by carbon deposits or changes in adjustment.

A further object of the invention is to construct a spark plug in which the electrodes are readily removable, and are furthermore accessible for the purposes of renewal without requiring the demounting of the entire plug. Both of the electrodes are of such construction that they may be very chea ly produced so that their renewal in the plh body is a source of veryinconsiderable expense and since the plug body is used as a permanent structure, the cost of up-keep of spark plugs, when pursued according to the methods permitted by my improved construction need be very small.

Vith the above objects in view and such other objects as may hereinafter appear, my invention will now be fully set forth and described, reference being had to the accom-- panying drawings.

In the drawings r- Figure 1 isa longitudinal elevation of the spark plug,

Fig. 2 is a longitudinal section thereof,

Fig. 3 an end view,

Fig. 4 is a view of a blank used in the manufacture of one of the terminals, and

Fig. 5 is a detailed elevation of the other terminal.

Referring to the drawing, there is shown a metallic casing 1 which is exteriorly threaded in the usual maner to engage the corresponding opening leading to the exploding chamber of an explosive engine cyl- The casing 1 is formed exteriorly inder. angular 111 its d mer portion as shown at 2 to receives. wrench, as usual, and incloses a Specification of Letters Patent. Patented B131. 5, 1918.

Serial No. 124,578.

chamber 3. In the construction illustrated,

the end wall of the casing opposite to the ally at-its central portion and dished with resultant sparking points 7 in mutual spaced relation and touching a common plane. The marginal portion 5 of the disk is provided with perforations 8- through which are engaged screws that take into the threaded recesses in the end wall of the plug casing and serve to hold the disk removable to the casing. iVithin the chamber 3 is mounted the opposite terminal 10 which, as best seen in Fig. 5 is an elongated stem which terminates at its lower end in a conical base 11 and a screw threaded foot 12. The latter is adapted to be received in a head 13 which is seated upon the bottom of the chamber 3 within the plug 1 and forms the upper end of a. rod or step 14, which extends through the bottom. ,of the casing 1, and is surrounded by a. suitable insulating sleeve 15. The stem 14 is-also insulated from the casing 1 and the wall 2 by means of the insulating disk 16 and the-collar 17. The/stem 14 serves to hold the parts in assembled relation, a lock nut lgjhreaded upon the upper end of the stem 14 hearing against the insulator 15 and locking the several .parts together, it being remembered that the head 13 bears upon thvbottom of the chamber 3. The binding screw 19 above the lock end 18 provides a suitable means for connecting a lead wire to a'comparatively simple matter to adjust the points with relation to the electrode 10 so that a certain operation of the plug assured: Furthermore, the terminal 10 is as easily renewed without disturbing the assemblage of the stem'14 or the remaining parts of the plug other than to remove the terminal 5. The device is simple and inexensive in manufacture, and may be used indefinitely as a complete device merely by the renewal of one of the terminals at-in frequent intervals as the occasion may re'-' 1. A removable terminal for spark plu consisting of a disk having perforations in its marginal portion to receive attaching means and having its central portion radially slitted and dlshed with resultant sparking points in mutual spaced relation and touching a common plane at right angles to the axis of the disk.

and having its central portion radially slitted and dished with resultant sparking points in mutual spaced relation and a sec- 0nd terminal carried by and insulated from the casing in sparking relation to said points.

In testimony whereof, I ailix my signa ture, iii the presence of two Witnesses.

ALFRED ST. JAMES. Witnesses:

' MARY A. Pmcocx,

EDITH V. Aomzw. 

